In applications such as motor drives and power conversion circuits, semiconductor switches repeatedly turn on and off a load current through an inductive load such as transformer coils or motor windings. Typically, free-wheeling diodes are electrically connected in parallel to the inductive load or parallel to the semiconductor switch. After shutting-down the load current, the free-wheeling diode gets forward-biased and allows the inductive load to dissipate the energy stored in its magnetic field.
In half-bridge circuits, e.g., in H-bridges for motor drives or at the primary side of half-bridge converters a free-wheeling diode that gets forward-biased when the high-side switch turns off is typically connected in parallel to and combined with the low-side switch and a free-wheeling diode that gets forward-biased when the low-side switch turns off is typically connected in parallel to and combined with the high-side switch. Device parameters such as blocking capability of the free-wheeling diode and blocking capability of the semiconductor switch typically match, wherein device parameters such as blocking voltage, on-state resistance, and switching losses are in relationship to each other in a way such that, e.g., higher blocking capability means higher on-state resistance and/or higher switching losses in the semiconductor switches.
It is desirable to provide electric assemblies that include semiconductor switches and that combine low switching losses with high reliability.